Process of treating shale or the like



Patented June 5,1928.

UNITED' STATES I 1,672,231 PATENT OFFICE.

HENRY 1). RYAN, or DENVER, COLORADO.

rnoonss or TREATING SHALE on THELIKEYI No Drawing, Application filed. January 2, 1920,5eria1 No. 348,905. Renewed August 23, 1927.

This invention relates to processes of treatingshale or the like; and it has to do more particularly with the treatment of bitumeniferous solids, such as shale, wherein a mixture comprising finely ground or pulverized shale with a hydrocarbon oil, most desirably a heavy hydrocarbon oil, is digested with the aid of heat under conditions such that the bitumens contained in the shale or other solid being treated are wholly or to a very great extent liquefied andextracted, while at the same time temperatures so high as to occasion drastic cracking in the digestion retort and consequently undesirable separation of free carbon and coky matter are avoided; the relatively light oil frac tions which distil off during the digestion being suitably recovered, and the residual fluid digestion mixture being [thereafter treated for separation of undissolved or unliquefied solid matter, in order to obtain a heavy oil mixture from'which valuable fractions and bituminous products, such as lubricating fractions, wax, etc. may be produced by suitable refining operations.

The present application is in part a continuation of my co-pending application Serial No. 225,344, filed March 28, 1918, now

Patent No. 1327572, in which the broad process involving digestion of shale and'the like with a hydrocarbon oil is describedand claimed. I have discovered, however, that in the commercial practice of the process disclosed in my co-pending application aforesaid, it is a matter of vital importance to ensure complete reduction of the shale or other bitumeniferous solid to a finely ground or pulverulent condition, in orderto attain an entirely satisfactory extraction of the bitumens contained in said shale or the like. I have found in fact that a reduction to a degree of fineness such that as much as 50 of per cent or more of the solid mineral mat ter will pass a 200 mesh sieve, is highly desirable in practice, although the benefits of the present invention can be realized in. some degree where the grinding or pulverization is not carried so far. In any event, it is important that, either before or during digestion, the comminution or reduction of the shale or other oil-bearing rock or sand should be carried substantially further, both as to degree and uniformity of fineness, than is attainable by ordinary crushing or comminuting methods, as distinguished. from What is properly grinding or pulvcrizing.

The reduction of a bitumeniferous rock such as shale orthe like, to the degree of fineness contemplated'by the present invention is difficult to effect by ordinary methods. If an oil-bearing shale be subjected to the action of grinding or pulverizing mechanism, it is found that it resists pulverization and tends to formcoherentcmasses such as.

flakes or the like instead of pulverizing. I have found that this difficulty can be overcomeif the shale or other oil bearing rock, preliminarily crushed to suitable size, say half-inch mesh or smaller, be ground at. a

somewhat elevated temperature, which mayv vary with different shales, but which in'a typical instance may range from 300 to 400 degrees F., for example. When so heated, the shale becomes friable and disinte grates readily under the actionv of grinding or pulverizing mechanism, the operation be.- ing advantageously carried tube mill, for example.

In treating shale or the like in accordance with the process of the present invention, the.

grinding or pulverization of the shaleto be treated, may be carried out as astep pre liminary to digestion, or it may be combined with the digestion itself. For example, shale crushed to half-inch or quarter-inch out in a ball, or

mesh, may be mixed with an equal volume or more of a hydrocarbon oil, preferably a heavy hydrocarbon v oil, such as a heavyshale oil fraction, for instance, and the mixture may then be heated in suitable apparatus adapted for combined grinding and digesting, such, for example. as a rotary digester containing grinding pebbles or balls. Under these circumstances, the later stages of the pulverization may take place at temperatures considerably exceeding those above specified as desirable for the grinding or pul.

verizing operation, the temperature of digestion eventually attained by the mixture in the digester commonly approximating 600 degrees F., or even somewhat higher in the case of certain shales which seem to require temperatures of between 600 and 700 degrees solid mineral matter finally remaining will pass a 200 mesh sieve.

I \Vhile the invention is not limited to simultaneous grinding and digesting of the bitumeniferous solid matter to be treated, that form of the invention, just described, offers special advantages for the reason that the agitation and progressive reduction of the crushed shale by the grinding balls or pebbles during the digestion has the effect of constantly clearing away and removing insoluble matter from the surfaces of the mineral fragments and particles undergoing treatment, fresh surfaces being thus continuously and progressively exposed to the action of the hot digestion medium as the pulveriZing and digestion proceed simultaneous- 1y. certain highly desirable characteristics which go to increase the-efliciency of the operation and the completeness with which the extraction of bituminous matter from the oilbearing solid is accomplished.

Instead of simultaneously grinding anddigesting the shale, as above described, it is feasible to preliminarily grind the shale, suitably heated as explained, and then to digest the pulverulentshale in mixture with a digestion oil.

During the digestion of the mixture of shale and oil, certain lighter fractions are vaporized and are conducted away from the retort to any suitable means such as one or more condensers for recovery of valuable light oil products such as kerosene,.gasoline, for example. The digestion should be so conducted, however, as not to distil off heavy fractions to a great extent. The residual digestion mixture may be treated in any suitable manner for separation of the solids contained therein from the accompanying oils and other liquefied heavy bitum'ens associated therewith. According to one method, to which the invention is not, however, to be understood as restricted, this separa- This type of treatment therefore hastion may be effected by diluting the digestion mixture with a lighter oil such as kerosene, for example, whereby separation of the solid matter in any suitable way such as by settling or sedimentation is facilitated and expedited. In effecting this dilution, care should be taken not to reduce the temperature of the mixturelow enough to cause separation of the heavier bitumen content such as wax or the like, at this stage. If the separation be effected by sedimentation or settling, the supernatant body of oil may be decanted or otherwise conducted away from the settlings, and may then be treated in any well known or suitable manner for further refining and separation into desired fractions, the heavier fractions, or a suitable part thereof, being most desirably utilized for digestion offurther quantities of shale in the digestion retort.

The process can be carried out in any suit.

able apparatus adapted for effecting the described treatment of the bituminous shale or other material. For example, the apparatus disclosed in my aforesaid co-pending application, but modified by employing a combined grinder and digester in place of the digester with rotary cylindrical screen agitator therein shown, will serve; but obvious- 1y other arrangements of apparatus than this specific type can be employed for carrying out'the novel process. I

What I claim is: I The process of treating bituminous shale or like mineral matter, which comprises simultaneously grinding and digesting bitu minous shale 1n mixture with a hydrocarbon oil at temperatures suiiiciently high to liquefy shale bitumens, while so limiting vaporization as'to obtain a final digestion mix,- ture which is fluid, and separatingresidual solid matter from such mixture.

In testimony whereof I hereunto affix my signature.

HENRY 1 RYAN, 

